Richard Lewontin, Alexander Agassiz Professor Emeritus of Zoology at Harvard University, is one of the world's most eminent authorities on human diversity. He has written many celebrated books on evolution and human variation books including Human Diversity, Not in Our Genes and most recently, The Triple Helix.

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Does racial difference exist on a genetic level?

Peoples who have occupied major geographical areas for much of the recent evolution of humans look different from one another. Sub-Saharan Africans have dark skin and people who live in East Asia tend to have a light tan skin and an eye color and eye shape and hair that is different than Europeans. So there is this kind of genetic - it is genetic - differentiation of some features of the body between people who live in Central Asia, Africa, Europe, North America, and South America.

And those features, which are geographically determined, were used to erect notions of different races. There's the African race, the Black race, the Yellow race, the Red race, the Brown race, and the White race. And it's mostly skin color plus hair shape and eye shape and so on. That's the everyday observation, that "they" all look alike - and we all look different.

The real question is not whether those differences in skin color and hair form are genetic, because they are. We know that because the children of black slaves brought to North America were the same color as their parents were. The question is what else does that tell us about biological differences? How much difference in other genes beside the genes that are relevant to skin color is there between these major geographical groups?

If we want to use the notion of race in a sensible, biological way, we could only do that if there really were a lot of genetic difference between those groups aside from the superficial differences that we can see. And that's an important issue which we now understand. We understand it because over the years a lot of data were gathered by anthropologists and geneticists looking at blood group genes and protein genes and other kinds of genes from all over the world. Anthropologists just went around taking blood out of everybody.

I must say, if I were a South American Indian, I wouldn't have let them take my blood, but they did. And one of the consequences of that is by the early 1970s, we had a huge amount of information about the different genetic forms all over the world for a large number of genes that had no relevance to those outward manifestations like skin color, but had to do with blood type and proteins.

And when you brought all that together, it became pretty clear that there really were minor differences in the frequencies of the different gene forms between the major geographical so-called races.

Since the 20th century, it's been recognized that there's what's called polymorphism of blood type. There are type As and type Bs and type Os and Rh-positive and Rh-negative and so on in every group in the world. But the assumption was that people in Africa would have a very different relative frequency of A and B and O than people would in North America or in Europe and in Asia.

And what all these studies showed was that that wasn't true. That you couldn't really tell the difference between an African population and a European population and an Asian population by looking at the frequency, the relative proportions of the different blood types. They were essentially the same in all these groups.

That isn't true for every blood type. There are occasional types which are strongly differentiated between populations. There's one blood type called the Duffy blood type and that's very different between Asians, Africans, and Europeans. But that's an exception rather than a rule.

For almost every gene we know, either everybody in the world has the same form of the gene, in which case all human beings are the same, or if there's variation, the frequencies of the different variants are the same relatively speaking, close to the same, in Africans, Asians, North Americans, Austro-Asians, and so on. And only about - well, I estimated 7% of all of human genetic variation could be ascribed to differences between groups, between major races. Anyway, about 75% of all the genes [come in only one form and] are identical in everybody. So there's very little differentiation.

How do you measure human genetic variation?

The way we measure human variation genetically is to look and find all the different forms of a particular gene, the alternative forms of a gene, and then see what percentage of the population has form one, form two, form three, form four, form five, and so on. Now if 99% of the population has one form and only 1% has another then there isn't much genetic variation in the population for that. And if different populations all have 99% of form one and 1% of form two, then there's no differentiation between populations because they have all the same percentages.

If on the other hand one population had 99% of form one and 1% of form two but some other population had 99% of form two and only 1% of form one, then even though within the population almost everybody is the same, between the populations there'd be a big difference.

So that's the way you characterize it. You see the percentages of the different forms in different populations and you ask -- If I take a sample from one population, are proportions of the different forms similar whether it's an African population or an Asian population or a European population? If so, there's no difference BETWEEN populations, and all the difference is found WITHIN populations.

So what did you discover about population differences?

Well, the problem back then for evolutionists and population geneticists was always to try to actually characterize how much genetic variation there was between individuals and groups and so on. And nobody knew how to do that because you had to connect genes with some outward manifestation that you could actually observe, and most genes don't have an outward manifestation in their variation.

So people didn't really know whether individuals varied genetically a lot from one another or only a little bit. They could see variation between individuals but they didn't know how much of all the genes that variation represented. And for a very long time, nobody had the faintest idea how genetically variable our species was from individual to individual.

And I spent a lot of time worrying about that like other people in my profession. And then I met a guy who had an experimental gimmick and he didn't know what to do with it, but I knew what to do with it. So I was sort of a person with a problem without a method and he was a guy with a method without a problem and we got together.

And that method was essentially to extract proteins from individuals and to run them in an electric field and to see whether the proteins moved at different rates in an electric field. If there were alternative forms of the genes that were for that protein, then the proteins would move at a different rate in the electric field, and you could visually identify the proteins by staining them.

So what you did is you ground up a fruit fly, you stuck it in a slab of jello, you turned on the current, all the proteins moved in the jello, and you turned off the current. You stained it, and sure enough you would see that different individuals had the same protein moving different distances. And that would be because they had a different form of the same gene.

And that method, which is called gel electrophoresis, a very fancy name, we were able to use it on any organism at all. If you could grind it up, you could do it, and that included people. You didn't have to grind up the whole person, but you could take a little bit of tissue or blood; you could do it on flies, on mice, on plants, on bacteria, anything. And the result was for 20 years people interested in this question of genetic variation were grinding up organisms and measuring the genetic variation.

And what they discovered was that organisms within a species were tremendously genetically different one from another. Many people had said, "No, they're all the same because any genetic differences are mutations and they will be selected out by natural selection. And except for a few superficial differences, everybody in a species is the same."

But that's not true. It turns out that between 25-33% of genes within a species are of the variable kind. They differ from one individual to another. And that's what that method discovered, that something around a quarter or a third of all your genes -- not your genes, but genes of any organism -- are variable between individuals of the species. So that gave us a different view of the possibility of evolution. And I thought, "Well, this raises the possibility that we could ask how much genetic differentiation there is between humans in different population groups."

It had already been established by a guy named Harry Harris that there was a lot of this genetic variation in humans, the kind that we have found in fruit flies, that people have found in plants. He used the same technique and showed that humans are genetically variable. But what he didn't know was how much difference there was between Africans and Asians and Europeans and so on. But a certain amount of that data began to accumulate, and by 1972 a lot of those data existed.

We could then tell from older data on human blood groups, which were known for a long time, and from this more recent data on their proteins which we could visualize in these gels, how much difference there was between any two individuals genetically and between a collection of individuals from France and a collection of individuals from French Equatorial Africa, and from Asia. And that collection of data is now huge, I mean, we know an immense amount about that kind of protein variation in humans. That was before people were sequencing DNA. That's when we were just looking at people's proteins.

And so I thought, "Well, we've got enough of this data, let's see what it tells us about the differences between human groups." And so I just looked into the literature, and that literature was in books and so on. And so one day I was going to give a lecture, I think it was in Carbondale, Illinois, or somewhere south. I was working in Chicago at the time. So I took a couple of these books with me and a pad of paper, and a table of logarithms which I needed for this purpose, and a little hand calculator, and I sat on this bus trip for three or four hours looking at the books, picking out the data, looking it up in the table of logarithms, doing a calculation, and writing it down in tables.

And when I got back after the round trip I had all the data I needed to write the paper about how much human genetic variation there was, and so I did it. And that's been repeated in recent years using DNA and so on. You always get the same result. Shows you it's worthwhile being afraid to fly, by the way, because you have lots of time on a bus to work.

So how much difference is there between human groups?

And the numbers come out as follows:

Roughly speaking for human beings, for about three-quarters of all our genes, everybody in the world, except a rare individual, has only one form of the gene. So all human beings share that form. For the 25%-33% or so of those genes for which there is some variation - 99 to one or 50/50 or 75/25 of different forms - for almost all of those genes, it doesn't matter from which population you take the sample; they have the same proportions. That is to say, if it's 75% of Form One and 25% of Form Two in Europeans, it's 70% of Form One and 30% of Form Two in Africans and 73% of Form One and 27% of Form Two in Asians, and so on. Most genes are like that.

But there are a very few genes, like the Duffy blood group, in which in Asian populations there is one very common form, in African populations there are two forms, but they're not the same as the common one in Asians, and in Europeans there's another different ratio. So for that gene, there's a big difference in the frequencies, but that's rare.

And if you put it all together - and we've now done that for proteins, for blood groups, and now with DNA sequencing, we have it for DNA sequence differences - it always comes out the same: 85% of all the variation among human beings is between any two individuals WITHIN any local population, 85% of all the variation; please remember that 75% of all genes are identical for everybody. But of the variation there is, 85% of that is between individuals within Sweden or within Denmark or within the Ewee or the Ki-kuyu or the Chinese or something.

Of the remaining 15% of human variation, it's roughly a 50/50 split of the variation between nationalities within what used to be called a major race, between Swedes, Italians, French, and so on, or between Ewee and Ki-kuyu and Zulu or something. And the other remaining 7% or so is between those major groups -- the blacks, browns, yellows, red, and whites.

What does that tell us about race?

Well, it might have turned out that there were big genetic differences between groups, and that most genes were highly differentiated between the major races. Now, if that turned out to be true, then at least it would be a possibility, although not demonstrated, that there might be, as some like to dream, high differentiations between groups in their mental abilities or in their temperaments or anything like that. Although nobody knew about any genes for those things, at least it was a living possibility.

But when we found that there were practically no genetic differences between groups except skin color and body form and a few things like that, it became a great deal less likely and less interesting to talk about genetic differences between groups. And the consequence is that from the biological standpoint those major so-called races - black, brown, yellow, white, and red - were not biologically interesting.

And that in turn meant that the differences that people were constantly emphasizing for social purposes were social constructs which almost certainly didn't have any biological basis. And therefore we should stop talking about major races because to talk about major races gave the impression that there were big differences between these groups in things that mattered - I mean, skin color, after all, doesn't matter except in some vague aesthetic sense - but things that really mattered: people's characters, their intelligence, their behavior, whether they're going to compete with other people or not and so on. The evidence then became that there weren't any interesting differences in such things, and so we should stop talking about race.

What causes different skin colors?

Well, the fact of the matter is that geneticists don't know anything about the genes that influence most characteristics of human interest. In fact, we don't even know where and how many genes there are that influence skin color - which is certainly influenced by genes, we know that. We don't know how many genes there are. We don't know where they are. We don't know anything about genes for schizophrenia or manic depression or dependency on drugs. Nothing. Zero. People keep making claims, and they take them back again.

Now why it is that people in these different groups evolved different skin colors is an open question. Nobody knows that. People have tried to tell us stories about it - stories like, well if you live where there's a lot of sun it's a good thing to have black skin so you wouldn't get skin cancer. But that really doesn't work, because it is true, you're more likely to get skin cancer if you get a lot of sun and you don't have dark skin, but that skin cancer doesn't come on until you're past your reproductive age anyway. So that wouldn't have any effect on your evolution.

The best guess these days is that the reason that people have different hair forms and eye shapes and skin colors, those outward manifestations, is something that Darwin called sexual selection. For some crazy reason which I can't understand, people in Europe liked washed-out looking people and they tended to select them for their mates, and the consequence is the Europeans became washed-out looking. Whereas people in Africa preferred dark people and so they became dark just by selective mating. And it would be exactly those outward manifestations like eye shape and hair shape and skin color that would have that effect.

Nobody can select their mate on the basis of blood group because you don't know what your mate's blood group is. So for those things which couldn't be subject to this kind of visual selection, mating selection, no differentiation occurred.

Why do people still hold on to biological explanations of difference?

Well, first of all, race is a social reality. I mean, there are people who are dark skinned and they are called black, and that's a social reality. You can't deny that. The question is why people hold onto that social reality. There are two reasons, one optimistic one, mainly that just because an idea changes or is seen to be without a basis, it doesn't go away right away. It takes time as human generations go on.

But more than that, race and racial categorizations serve a very important social function, namely, they justify the inequalities that exist in a society which is said to be based on equality. Why is it that if all men are created equal - not women, notice, but men - if all men are created equal, then why is there a much greater proportion of black people in jail than white people?

Is it possible that people are not treating them fairly? "No," you say, "that can't be, because we live in a society of equality." So the easy answer is, "Well, they're in jail because more black people ought to be in jail because black people have genes that make them criminals." And the beauty of that ideology that it justifies what is the greatest social agony of American life, certainly, and partly, European life - namely, the huge social inequalities between groups in a society which claims to be a society of equality.

And you have to cope with that, you have to somehow become at ease with it, because the alternative is to demand a real revolution in social relations, and that's not easy to do.

What is biological determinism?

Biological determinism is this notion that everything that's important about human beings and the differences between them and their position in the world is determined internally by their biological natures. And I think in our world, the importance of biological determinism really goes back to the American Revolution and the notion that we were going to build a society of equality. "All men are created equal; they're endowed by their Creator with certain inalienable rights, etc."

And the problem with that is, you look around and you see people don't have equality of wealth or power or status. And the problem then, is to explain how it is that in a society which is supposed to be built on equality there's so much inequality. And that was a problem that also bothered the English as well and the French in the 19th century; everybody was concerned with explaining tremendous social inequalities despite the fact that they were living in these societies which revolutions had occurred to make equality.

And there are really only two solutions to that problem. Either it was all fake to begin with - maybe the revolutions weren't really meant to produce equality; they were just meant to get some people in power instead of the old people - or the alternative is people are as equal as they can be. The reason they're not more equal is because there are in-built, unchangeable, blood-determined differences between them. (When they said blood, now we talk about genes. But it's the same thing.) Society has just equalized as much as it can and the people now who are in superior position are there because of their biological natures.

So that social stratification, social differences, difference in status, wealth, and power are all largely a consequence of your biological nature, which is unchangeable. And that's what biological determinism is. The structure of society is fixed, and it's fixed for biological reasons.

And then there's another side to it. And the other side is you say, "Well okay, suppose it's really true that there are unchangeable differences between individuals. Some people by their biology could be professors and others could be only janitors." You could say, "Alright, I'll accept that, but maybe we should have a society in which both professors and janitors who are all doing socially useful work, I guess, are rewarded equally. Why should society give differential rewards just because some people can do one thing and other people can do another?"

And then we have a new form of biological determinism, the kind of thing you see in evolutionary psychology and socio-biology, which says, "Well, but it's part of biological human nature to create hierarchical societies." So it's impossible biologically to make a society in which everybody gets equal status and wealth and power because they'll naturally create this hierarchies.

So biological determinism these days really has two forms, two aspects. One is that the differences between us are biologically determined and the second is that we all are similar in one very important respect, namely we all have human nature, and that human nature makes us produce hierarchical societies.

What is the relationship between your DNA and how you turn out as a person?

The word that geneticists use for a description of your outward manifestations and your physiology and your metabolism and your anatomy and so on, including your behavior, is phenotype - literally, "what appears," from the notion of pheno, to appear. And in theory that's supposed to be the result of the genes that you have, which are called the genotype.

The question that geneticists have been struggling with for a very long time is, What's the relationship between those elements in the genotype, the DNA, and what comes out at the end of the developmental process, the phenotype?

You have to remember, we start as a fertilized egg, and that egg goes through cell divisions and becomes a whole organism, and that organism develops throughout its entire life. We are all developing continuously. We get taller and then we get shorter. We get smarter and then we get dumber. That happens continuously.

So the question is, What's the relationship between those inner elements, those genes, the genotype, and the phenotype. And the answer that we know from years of experimental study and ordinary observation is that there's no simple one-to-one relationship between the genotype and the phenotype. The organism is certainly influenced in powerful ways by the genes - there is no chimpanzee that will be interviewed on television and say the things I'm saying now, because chimpanzees don't have the genes to enable them to speak, to form these abstract ideas, because their brains are not the right shape and so on.

So clearly differences between the species are, in some sense, in the genes. But at the same time it's not the case that every aspect of the phenotype is determined by the genes, because the environment in which you develop, both within the womb and after you're born, your whole psychic environment, your education, what comes in on you, the food you eat, the society you live in - all that goes to form the phenotype.

That phenotype can't be anything in the world. As I said, no matter what environment a chimpanzee lives in it'll never be a professor, although some professors might be sort of like chimpanzees. No matter what environment we live in, I think it's extremely unlikely that human beings will live to be 200 years old, for example, because of our genes.

Now, what's interesting about our phenotypes, about the variation of phenotypes between individuals, is that they sort of vary continuously - like heights or shapes or colors - there's not just three different colors or four different heights, yet the genes exist as discrete objects which have particular different forms. You can have form one of the gene or form two of the gene or form three.

So you have these discreet differences at the genotypic level, which are somehow converted into continuous variation between individuals and their behavior and their morphology and their physiology, and it's kind of like a pointillist painting, in which, if you stand back from the painting, you see continuous figures, but when you go up close to them you see that they're made by tiny little dots of paint which fuse together in your eyes and in your brain from a distance, but are discreet and individual.

And the observer who observers a pointillist painting is performing an action, is making the phenotype out of that underlying genotype, so to speak, by the intervention of their eyes and their central nervous systems. In the same way, our genotype is converted into a phenotype through the developmental process which is occurring in a particular environment. And every environment is different, and environments are changing all the time.

So there's a very complicated relationship between genotype and phenotype. People who say, "Well, if only I knew all your genes I'd know exactly all about you," are wrong. Indeed, the notion that if I cloned an individual by reproducing that person's genes in another individual, that the cloned individual would be identical with the ones from which the genes came, is wrong.

When I was a child, the most famous people in the world were the Dionne Quintuplets. The Quintuplets were five girls born in rural Quebec, all identical quintuplets. And they were dressed alike and they had their hair done alike and they looked alike, and they were put into a kind of zoo by their parents and by the doctor who delivered them and by the province of Ontario. And everybody looked at them and they were made as alike as they could be so they'd be the wonder of the modern age. They were clones of each other.

But in fact, when they got older, when they left this artificial environment, they became quite different from each other. A couple became nuns, some were married and some not, two died and three are still alive - I think a third one died recently. One was schizophrenic, the others weren't. They were as different from each other as any five girls could be, although they still looked pretty much alike.

And that's the important point: that although a lot of our morphology, a lot of our facial features appear not to be greatly influenced by environmental variation, our personalities clearly are tremendously influenced by it, and our abilities. And the Dionne quintuplets are a wonderful example.

Is it possible that genes could hold the key to social behaviors?

People are always talking about genes for things - the genes for athletic ability, the genes for making money, the genes for intelligence. And you have to be very careful. Even when there are genes that influence those things, to talk about them as genes for that is not so clear. And a friend of mine gave me a wonderful example. He said, "I know where the genes for knitting are." And I said, "How can you know where those genes are; what does that mean?"

And he said, "Oh, the genes for knitting are clearly on the X chromosome, the *** chromosome. Why? Because, after all, all the people I know who knit have two x chromosomes, and everybody I know who has one X chromosome and one Y chromosome doesn't knit, so the gene for knitting has to be on the X chromosome." And he's right, by the way, that that's the standard method used by geneticists: you find some genetic marker and you see that everybody who has that genetic marker has this trait, everybody who has a different genetic marker has another trait, so you've discovered the gene for it.

Now, when I say the gene for knitting, you're going to laugh, you're going to say, "That's silly. There can't be a gene for knitting. I know why people knit." And the reason that we laugh is because we know the whole story about the gene for knitting. We know that the genes on the X and Y chromosome are for plumbing, and X chromosome people have one kind of plumbing and people with a Y chromosome have a different kind of plumbing. Depending on which plumbing you're born with, you're socialized as either a female or a male. And if you're socialized as a female, one of the things you learn to do is to knit, and if you're socialized as a male, you don't learn to knit.

So, of course, people with two X chromosomes knit and people with one X and one Y don't knit. But you wouldn't want to say that the genes for knitting are there. The point is, we understand the complete developmental and social story about why people with two X chromosomes knit and people with one X and one Y chromosome don't knit. And what's nice about that story is it was exactly the opposite in the 18th century. In the 18th century the gene for knitting was on the Y chromosome, because only men did hand-knitting, not women!

And the reason why men gave up hand-knitting and left it their wives to do at home is because someone invented the knitting machine and the men went into the factory and did knitting on knitting machines and left the now economically useless work to their wives at home. So maybe what we should say that we know that the X chromosome has the genes for doing economically useless work, and the Y chromosome for doing economically useful work.

When you put it in those terms, when you really know the complete story, you stop talking about genes for this and genes for that, and you talk about genes having some influence on certain physiological anatomical traits, which are then used as cues by other people.

So, let's talk about race. I know where the genes for being incarcerated are. They're the skin color genes. Now, that doesn't mean that those genes cause you to be incarcerated. What those genes do is to cause you to have a certain skin color, and social relations and social arrangements are such that people who have dark skin color are incarcerated more than people who don't have dark skin color, but the genes don't make you incarcerated. You have to make that distinction very clearly.

What do you think about new trends in genetics research?

The so-called "new genetics", which just puts the action of these biological factors onto a molecular scale, is still as deterministic as ever. People who are doing molecular genetics, who are mapping genes in human beings, are trying to find the genes for schizophrenia, the genes that are responsible for all sorts of diseases.

The editor of Science magazine, the most prestigious general science magazine, once was asked why we should spend a lot of money on the human genome project when we have all those poor people and homeless people out there, and his response was, "The best way to get rid of homelessness is to study people's genes because homelessness is in the genes."

So the genome project and molecular genetics are simply a new manifestation of an old idea - or they're created with that same bias, namely, the reason we're studying all the genes is because genes determine everything. If you didn't think genes determined what was really important in life, then why would you go and spend all this money and time studying the human genome?

Look, people said, when the human genome project was floated, once we know what the human genome is, when we see all the genes, we'll know what it is to be human. A very famous biologist said that. So if you really think you'll learn what it is to be human by studying human genes, that's why you study them. But of course, we won't know what it is to be human by studying the genes. That's the error. But nevertheless, that's what the modern manifestation of biological determinism is.

Let's take the argument [about genes and homelessness] as the editor meant it. What he's saying is, Why are people homeless? Many homeless people are de-institutionalized mentally ill people or people who have been on drugs or things of that kind. Why are they on drugs? Because they have a biological dependency on drugs. Why are they mentally ill? Because they have genes that make them mentally ill. So that was his reasoning.

Homelessness is not, for him, simply the usual manifestation of economic inequality. People who are homeless are homeless because they're in one way or the other sick, and knowing the genes will cure all the diseases. That's his claim. Especially drug dependency, schizophrenia, manic depression, and so forth. They're all due to genes according to that view. Of course, people have been struggling to find the genes for schizophrenia and manic-depressive syndrome for a long time and they haven't found them. Or rather, they keep planning to find them and then six months later they write a paper saying, "Oh, we made a mistake. They're not there."

Is biological determinism another form of racism?

Biological racism is just another manifestation of the belief that everything is in the genes. So of course, if people in Africa are not as well off as people in Europe, it's because they have genes that make them less intelligent and less ambitious, and so on. And the beauty of the race business is that you can identify people by just looking at them. You don't even have to look at their genes because one manifestation of their genes is there - namely skin color or eye shape or hair shape - and then that's the key to everything.

So racism, that kind of biological racism is just part of the general ideology that everything important is in the genes. And of course, if people look different then they must have different genes, and to some extent they do have different genes. And that will explain why slaves were black and masters were white. So racism is part and parcel of that whole thing.

Where do our ideas of biological determinism come from?

Biological determinism, which is a desire to understand social inequality, was really built into most 19th century English literature. ****ens, whose the great mystery novelist of the 19th century - all of his mysteries are about the same thing: How do we explain the character people have? Is it upbringing or is it internal? And he believed it was internal.

Oliver Twist is the most famous example of that. You have to remember Oliver Twist was born in the workhouse, which was the place you had to go to get relief after the New Poor Law of 1834. And his mother was in the workhouse. He was born in the workhouse, he had no education, he was living with all these other kids on gruel, picking oakum, doing all the things that little kids in the workhouse did.

And then when he left the workhouse without any education, without any culture, without anything, we find him on the road to London. And he meets on the road to London the Artful Dodger, a kid somewhat older than he was, a teenager. And the contrast between Oliver and the Artful Dodger which is drawn by ****ens is extraordinary. Because the Artful Dodger doesn't speak good English; he drops all his G's; that's the thing that you would expect a poor kid from the slums of London to do. And here's Oliver; he's described as a delicate child, he uses the subjunctive, his grammar is perfect. Where did he learn all that - in the workhouse, the most degraded institution of 19th century Britain?

Well, that's the mystery. The mystery of Oliver Twist is how do we explain the contrast in character between Oliver Twist on the one hand and the Artful Dodger on the other, both of whom were brought up under essentially the same miserable circumstances.

And at the end of the book you discover that Oliver actually had upper-middle class parents. And even though he never saw them because his mother died in childbirth and he never saw his father, the true nature of that upper-middle class "blood" came out in him, and so he was a child of great moral character. He was honest, he was delicate, he used good English, and so on. And that was a working out of that notion, that what really matters about character is what's inside, not what's outside.

And he's not the only one. There's the wonderful story of George Elliott, Daniel Deronda, one of George Elliott's heroes. We're told right away he's the adopted son of an English baroness, and he has all the behavior of the young lord. We meet him in a fashionable watering place and gambling casino in Germany.

And then mysteriously around the age of 20 or 21, he falls in love with a Jewish woman. Now this is early 19th century Britain. That doesn't happen every day of the week. The baron falls in love with a Jewish woman. He learns the Talmud, he converts, and he becomes a Zionist; he actually is one of the earliest people to want to go to Palestine. What's the secret? How do you understand that strange business?

It turns out - and you only discover this at the end of the book - that his mother is a famous Jewish actress who he finally meets when he's an adult and it all came through, and he became what his genes made him. So ****ens is not the only one. And that's true in French literature, it's true in all literature of the 19th century.

Aren't groups like Icelanders genetically distinct because they've been more isolated?

Iceland has been in the news a lot recently because the Icelandic government has awarded the entire Icelandic genome to a private company to exploit. The claim of this company is that the reason why they want to have the genotypes of all Icelanders is because Icelanders are uniquely homogenous people. And why are they uniquely homogenous? Because, the story is, Iceland was founded in the 9th century by people who came from Norway - a very small number of people who came from Norway, just these immigrants. There was nobody in Iceland when they arrived - that's true - and all Icelanders at the present time are descended from those few immigrants at the very beginning, and therefore Icelanders are all related to each other very closely, and therefore if somehow we could study their genes we could find the genes for disease and other things because everybody's related to everybody, and we could carry out the pedigree.

And so the whole thing is based on the claim that Iceland is extremely homogenous, genetically. Now, that's bolstered by the fact that Icelanders speak a language which elsewhere has been dead for 1500 years; that is to say, they speak a form of Old Norse which is related to Norwegian and Swedish but very different. And also they are claimed all to look alike - they're all sort of reddish-haired or blond and so on - and they're isolated and they all know each other; it's a very small country, only a couple hundred thousand people.

So all of that comes together, this notion that Iceland is a genetic isolate, a few people came there, they've been genetically isolated from everybody ever since, and that's why they speak this crazy language and everything is homogenous.

Now, the trouble is that we know that that's not true, and we know it from a source which is in one sense the source of Icelandic national pride, which is the Icelandic Sagas. The Icelandic Sagas, which were composed or spoken verbally during the Middle Ages by a variety of Icelandic authors and eventually written down, tell us the story of the founding of Iceland, of the wars that the Icelanders, the Vikings, engaged in.

And they give this impression at first that it's a very homogenous society. But when you begin to read the sagas, what you discover is that those early Icelanders, those Vikings, were in fact making a living doing exactly the same thing that the Ancient Greeks were doing: namely, half the time they spent farming, and then half the time they were pirates. They got in their boats, and they went around raping and pillaging and taking slaves and just warring everywhere, and that's what Vikings were. Vikings were pirates. And they didn't try to excuse it; that was the way of life the Sagas described.

And in the process of that piratical existence, they took slaves, they brought people back to Iceland from other countries. There a wonderful place in I think it's Egil's Saga, which is a story of a guy who wants to buy a concubine. So he goes to Russia and he deals with a Russian trader, and the Russian trader asks him a certain price for this concubine. He said he had a dozen of these women in his hut. And the Icelander says, "Wait a minute, I'm not going to pay that. That's much more than the usual price for a woman slave."

So there was a usual price, which meant that Icelanders were doing this all the time. They were getting women and bringing them back. If you look around northern Scotland, you see lots of town names - this "ness" and that "ness" - Loch Ness, Inverness, so on. Ness is an Iceland word; it means cape. Those are all the places the Icelanders landed and took their slaves. One of the sagas is all about the fighting in the Orkney Islands and how the Icelanders landed in the Orkneys and established their position there and so on.

So Iceland, in fact, is a place made up, yes, partly of descendants of those early Viking ancestors who fled from Norway to escape the king, but in large part also from slaves they took, from people they brought from all over, and became part of the Icelandic genetic pool. So Iceland turns out, in fact, when you look at Icelanders, when you look at their proteins, you look at their DNA, they turn out to be not any more genetically homogenous than Swedes, Germans, English, French, all of Northern Europe. They look like a typical Northern European country.

Richard Lewontin, Alexander Agassiz Professor Emeritus of Zoology at Harvard University, is one of the world's most eminent authorities on human diversity. He has written many celebrated books on evolution and human variation books including Human Diversity, Not in Our Genes and most recently, The Triple Helix.

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Does racial difference exist on a genetic level?

Peoples who have occupied major geographical areas for much of the recent evolution of humans look different from one another. Sub-Saharan Africans have dark skin and people who live in East Asia tend to have a light tan skin and an eye color and eye shape and hair that is different than Europeans. So there is this kind of genetic - it is genetic - differentiation of some features of the body between people who live in Central Asia, Africa, Europe, North America, and South America.

And those features, which are geographically determined, were used to erect notions of different races. There's the African race, the Black race, the Yellow race, the Red race, the Brown race, and the White race. And it's mostly skin color plus hair shape and eye shape and so on. That's the everyday observation, that "they" all look alike - and we all look different.

The real question is not whether those differences in skin color and hair form are genetic, because they are. We know that because the children of black slaves brought to North America were the same color as their parents were. The question is what else does that tell us about biological differences? How much difference in other genes beside the genes that are relevant to skin color is there between these major geographical groups?

If we want to use the notion of race in a sensible, biological way, we could only do that if there really were a lot of genetic difference between those groups aside from the superficial differences that we can see. And that's an important issue which we now understand. We understand it because over the years a lot of data were gathered by anthropologists and geneticists looking at blood group genes and protein genes and other kinds of genes from all over the world. Anthropologists just went around taking blood out of everybody.

I must say, if I were a South American Indian, I wouldn't have let them take my blood, but they did. And one of the consequences of that is by the early 1970s, we had a huge amount of information about the different genetic forms all over the world for a large number of genes that had no relevance to those outward manifestations like skin color, but had to do with blood type and proteins.

And when you brought all that together, it became pretty clear that there really were minor differences in the frequencies of the different gene forms between the major geographical so-called races.

Since the 20th century, it's been recognized that there's what's called polymorphism of blood type. There are type As and type Bs and type Os and Rh-positive and Rh-negative and so on in every group in the world. But the assumption was that people in Africa would have a very different relative frequency of A and B and O than people would in North America or in Europe and in Asia.

And what all these studies showed was that that wasn't true. That you couldn't really tell the difference between an African population and a European population and an Asian population by looking at the frequency, the relative proportions of the different blood types. They were essentially the same in all these groups.

That isn't true for every blood type. There are occasional types which are strongly differentiated between populations. There's one blood type called the Duffy blood type and that's very different between Asians, Africans, and Europeans. But that's an exception rather than a rule.

For almost every gene we know, either everybody in the world has the same form of the gene, in which case all human beings are the same, or if there's variation, the frequencies of the different variants are the same relatively speaking, close to the same, in Africans, Asians, North Americans, Austro-Asians, and so on. And only about - well, I estimated 7% of all of human genetic variation could be ascribed to differences between groups, between major races. Anyway, about 75% of all the genes [come in only one form and] are identical in everybody. So there's very little differentiation.

How do you measure human genetic variation?

The way we measure human variation genetically is to look and find all the different forms of a particular gene, the alternative forms of a gene, and then see what percentage of the population has form one, form two, form three, form four, form five, and so on. Now if 99% of the population has one form and only 1% has another then there isn't much genetic variation in the population for that. And if different populations all have 99% of form one and 1% of form two, then there's no differentiation between populations because they have all the same percentages.

If on the other hand one population had 99% of form one and 1% of form two but some other population had 99% of form two and only 1% of form one, then even though within the population almost everybody is the same, between the populations there'd be a big difference.

So that's the way you characterize it. You see the percentages of the different forms in different populations and you ask -- If I take a sample from one population, are proportions of the different forms similar whether it's an African population or an Asian population or a European population? If so, there's no difference BETWEEN populations, and all the difference is found WITHIN populations.

So what did you discover about population differences?

Well, the problem back then for evolutionists and population geneticists was always to try to actually characterize how much genetic variation there was between individuals and groups and so on. And nobody knew how to do that because you had to connect genes with some outward manifestation that you could actually observe, and most genes don't have an outward manifestation in their variation.

So people didn't really know whether individuals varied genetically a lot from one another or only a little bit. They could see variation between individuals but they didn't know how much of all the genes that variation represented. And for a very long time, nobody had the faintest idea how genetically variable our species was from individual to individual.

And I spent a lot of time worrying about that like other people in my profession. And then I met a guy who had an experimental gimmick and he didn't know what to do with it, but I knew what to do with it. So I was sort of a person with a problem without a method and he was a guy with a method without a problem and we got together.

And that method was essentially to extract proteins from individuals and to run them in an electric field and to see whether the proteins moved at different rates in an electric field. If there were alternative forms of the genes that were for that protein, then the proteins would move at a different rate in the electric field, and you could visually identify the proteins by staining them.

So what you did is you ground up a fruit fly, you stuck it in a slab of jello, you turned on the current, all the proteins moved in the jello, and you turned off the current. You stained it, and sure enough you would see that different individuals had the same protein moving different distances. And that would be because they had a different form of the same gene.

And that method, which is called gel electrophoresis, a very fancy name, we were able to use it on any organism at all. If you could grind it up, you could do it, and that included people. You didn't have to grind up the whole person, but you could take a little bit of tissue or blood; you could do it on flies, on mice, on plants, on bacteria, anything. And the result was for 20 years people interested in this question of genetic variation were grinding up organisms and measuring the genetic variation.

And what they discovered was that organisms within a species were tremendously genetically different one from another. Many people had said, "No, they're all the same because any genetic differences are mutations and they will be selected out by natural selection. And except for a few superficial differences, everybody in a species is the same."

But that's not true. It turns out that between 25-33% of genes within a species are of the variable kind. They differ from one individual to another. And that's what that method discovered, that something around a quarter or a third of all your genes -- not your genes, but genes of any organism -- are variable between individuals of the species. So that gave us a different view of the possibility of evolution. And I thought, "Well, this raises the possibility that we could ask how much genetic differentiation there is between humans in different population groups."

It had already been established by a guy named Harry Harris that there was a lot of this genetic variation in humans, the kind that we have found in fruit flies, that people have found in plants. He used the same technique and showed that humans are genetically variable. But what he didn't know was how much difference there was between Africans and Asians and Europeans and so on. But a certain amount of that data began to accumulate, and by 1972 a lot of those data existed.

We could then tell from older data on human blood groups, which were known for a long time, and from this more recent data on their proteins which we could visualize in these gels, how much difference there was between any two individuals genetically and between a collection of individuals from France and a collection of individuals from French Equatorial Africa, and from Asia. And that collection of data is now huge, I mean, we know an immense amount about that kind of protein variation in humans. That was before people were sequencing DNA. That's when we were just looking at people's proteins.

And so I thought, "Well, we've got enough of this data, let's see what it tells us about the differences between human groups." And so I just looked into the literature, and that literature was in books and so on. And so one day I was going to give a lecture, I think it was in Carbondale, Illinois, or somewhere south. I was working in Chicago at the time. So I took a couple of these books with me and a pad of paper, and a table of logarithms which I needed for this purpose, and a little hand calculator, and I sat on this bus trip for three or four hours looking at the books, picking out the data, looking it up in the table of logarithms, doing a calculation, and writing it down in tables.

And when I got back after the round trip I had all the data I needed to write the paper about how much human genetic variation there was, and so I did it. And that's been repeated in recent years using DNA and so on. You always get the same result. Shows you it's worthwhile being afraid to fly, by the way, because you have lots of time on a bus to work.

So how much difference is there between human groups?

And the numbers come out as follows:

Roughly speaking for human beings, for about three-quarters of all our genes, everybody in the world, except a rare individual, has only one form of the gene. So all human beings share that form. For the 25%-33% or so of those genes for which there is some variation - 99 to one or 50/50 or 75/25 of different forms - for almost all of those genes, it doesn't matter from which population you take the sample; they have the same proportions. That is to say, if it's 75% of Form One and 25% of Form Two in Europeans, it's 70% of Form One and 30% of Form Two in Africans and 73% of Form One and 27% of Form Two in Asians, and so on. Most genes are like that.

But there are a very few genes, like the Duffy blood group, in which in Asian populations there is one very common form, in African populations there are two forms, but they're not the same as the common one in Asians, and in Europeans there's another different ratio. So for that gene, there's a big difference in the frequencies, but that's rare.

And if you put it all together - and we've now done that for proteins, for blood groups, and now with DNA sequencing, we have it for DNA sequence differences - it always comes out the same: 85% of all the variation among human beings is between any two individuals WITHIN any local population, 85% of all the variation; please remember that 75% of all genes are identical for everybody. But of the variation there is, 85% of that is between individuals within Sweden or within Denmark or within the Ewee or the Ki-kuyu or the Chinese or something.

Of the remaining 15% of human variation, it's roughly a 50/50 split of the variation between nationalities within what used to be called a major race, between Swedes, Italians, French, and so on, or between Ewee and Ki-kuyu and Zulu or something. And the other remaining 7% or so is between those major groups -- the blacks, browns, yellows, red, and whites.

What does that tell us about race?

Well, it might have turned out that there were big genetic differences between groups, and that most genes were highly differentiated between the major races. Now, if that turned out to be true, then at least it would be a possibility, although not demonstrated, that there might be, as some like to dream, high differentiations between groups in their mental abilities or in their temperaments or anything like that. Although nobody knew about any genes for those things, at least it was a living possibility.

But when we found that there were practically no genetic differences between groups except skin color and body form and a few things like that, it became a great deal less likely and less interesting to talk about genetic differences between groups. And the consequence is that from the biological standpoint those major so-called races - black, brown, yellow, white, and red - were not biologically interesting.

And that in turn meant that the differences that people were constantly emphasizing for social purposes were social constructs which almost certainly didn't have any biological basis. And therefore we should stop talking about major races because to talk about major races gave the impression that there were big differences between these groups in things that mattered - I mean, skin color, after all, doesn't matter except in some vague aesthetic sense - but things that really mattered: people's characters, their intelligence, their behavior, whether they're going to compete with other people or not and so on. The evidence then became that there weren't any interesting differences in such things, and so we should stop talking about race.

What causes different skin colors?

Well, the fact of the matter is that geneticists don't know anything about the genes that influence most characteristics of human interest. In fact, we don't even know where and how many genes there are that influence skin color - which is certainly influenced by genes, we know that. We don't know how many genes there are. We don't know where they are. We don't know anything about genes for schizophrenia or manic depression or dependency on drugs. Nothing. Zero. People keep making claims, and they take them back again.

Now why it is that people in these different groups evolved different skin colors is an open question. Nobody knows that. People have tried to tell us stories about it - stories like, well if you live where there's a lot of sun it's a good thing to have black skin so you wouldn't get skin cancer. But that really doesn't work, because it is true, you're more likely to get skin cancer if you get a lot of sun and you don't have dark skin, but that skin cancer doesn't come on until you're past your reproductive age anyway. So that wouldn't have any effect on your evolution.

The best guess these days is that the reason that people have different hair forms and eye shapes and skin colors, those outward manifestations, is something that Darwin called sexual selection. For some crazy reason which I can't understand, people in Europe liked washed-out looking people and they tended to select them for their mates, and the consequence is the Europeans became washed-out looking. Whereas people in Africa preferred dark people and so they became dark just by selective mating. And it would be exactly those outward manifestations like eye shape and hair shape and skin color that would have that effect.

Nobody can select their mate on the basis of blood group because you don't know what your mate's blood group is. So for those things which couldn't be subject to this kind of visual selection, mating selection, no differentiation occurred.

Why do people still hold on to biological explanations of difference?

Well, first of all, race is a social reality. I mean, there are people who are dark skinned and they are called black, and that's a social reality. You can't deny that. The question is why people hold onto that social reality. There are two reasons, one optimistic one, mainly that just because an idea changes or is seen to be without a basis, it doesn't go away right away. It takes time as human generations go on.

But more than that, race and racial categorizations serve a very important social function, namely, they justify the inequalities that exist in a society which is said to be based on equality. Why is it that if all men are created equal - not women, notice, but men - if all men are created equal, then why is there a much greater proportion of black people in jail than white people?

Is it possible that people are not treating them fairly? "No," you say, "that can't be, because we live in a society of equality." So the easy answer is, "Well, they're in jail because more black people ought to be in jail because black people have genes that make them criminals." And the beauty of that ideology that it justifies what is the greatest social agony of American life, certainly, and partly, European life - namely, the huge social inequalities between groups in a society which claims to be a society of equality.

And you have to cope with that, you have to somehow become at ease with it, because the alternative is to demand a real revolution in social relations, and that's not easy to do.

What is biological determinism?

Biological determinism is this notion that everything that's important about human beings and the differences between them and their position in the world is determined internally by their biological natures. And I think in our world, the importance of biological determinism really goes back to the American Revolution and the notion that we were going to build a society of equality. "All men are created equal; they're endowed by their Creator with certain inalienable rights, etc."

And the problem with that is, you look around and you see people don't have equality of wealth or power or status. And the problem then, is to explain how it is that in a society which is supposed to be built on equality there's so much inequality. And that was a problem that also bothered the English as well and the French in the 19th century; everybody was concerned with explaining tremendous social inequalities despite the fact that they were living in these societies which revolutions had occurred to make equality.

And there are really only two solutions to that problem. Either it was all fake to begin with - maybe the revolutions weren't really meant to produce equality; they were just meant to get some people in power instead of the old people - or the alternative is people are as equal as they can be. The reason they're not more equal is because there are in-built, unchangeable, blood-determined differences between them. (When they said blood, now we talk about genes. But it's the same thing.) Society has just equalized as much as it can and the people now who are in superior position are there because of their biological natures.

So that social stratification, social differences, difference in status, wealth, and power are all largely a consequence of your biological nature, which is unchangeable. And that's what biological determinism is. The structure of society is fixed, and it's fixed for biological reasons.

And then there's another side to it. And the other side is you say, "Well okay, suppose it's really true that there are unchangeable differences between individuals. Some people by their biology could be professors and others could be only janitors." You could say, "Alright, I'll accept that, but maybe we should have a society in which both professors and janitors who are all doing socially useful work, I guess, are rewarded equally. Why should society give differential rewards just because some people can do one thing and other people can do another?"

And then we have a new form of biological determinism, the kind of thing you see in evolutionary psychology and socio-biology, which says, "Well, but it's part of biological human nature to create hierarchical societies." So it's impossible biologically to make a society in which everybody gets equal status and wealth and power because they'll naturally create this hierarchies.

So biological determinism these days really has two forms, two aspects. One is that the differences between us are biologically determined and the second is that we all are similar in one very important respect, namely we all have human nature, and that human nature makes us produce hierarchical societies.

What is the relationship between your DNA and how you turn out as a person?

The word that geneticists use for a description of your outward manifestations and your physiology and your metabolism and your anatomy and so on, including your behavior, is phenotype - literally, "what appears," from the notion of pheno, to appear. And in theory that's supposed to be the result of the genes that you have, which are called the genotype.

The question that geneticists have been struggling with for a very long time is, What's the relationship between those elements in the genotype, the DNA, and what comes out at the end of the developmental process, the phenotype?

You have to remember, we start as a fertilized egg, and that egg goes through cell divisions and becomes a whole organism, and that organism develops throughout its entire life. We are all developing continuously. We get taller and then we get shorter. We get smarter and then we get dumber. That happens continuously.

So the question is, What's the relationship between those inner elements, those genes, the genotype, and the phenotype. And the answer that we know from years of experimental study and ordinary observation is that there's no simple one-to-one relationship between the genotype and the phenotype. The organism is certainly influenced in powerful ways by the genes - there is no chimpanzee that will be interviewed on television and say the things I'm saying now, because chimpanzees don't have the genes to enable them to speak, to form these abstract ideas, because their brains are not the right shape and so on.

So clearly differences between the species are, in some sense, in the genes. But at the same time it's not the case that every aspect of the phenotype is determined by the genes, because the environment in which you develop, both within the womb and after you're born, your whole psychic environment, your education, what comes in on you, the food you eat, the society you live in - all that goes to form the phenotype.

That phenotype can't be anything in the world. As I said, no matter what environment a chimpanzee lives in it'll never be a professor, although some professors might be sort of like chimpanzees. No matter what environment we live in, I think it's extremely unlikely that human beings will live to be 200 years old, for example, because of our genes.

Now, what's interesting about our phenotypes, about the variation of phenotypes between individuals, is that they sort of vary continuously - like heights or shapes or colors - there's not just three different colors or four different heights, yet the genes exist as discrete objects which have particular different forms. You can have form one of the gene or form two of the gene or form three.

So you have these discreet differences at the genotypic level, which are somehow converted into continuous variation between individuals and their behavior and their morphology and their physiology, and it's kind of like a pointillist painting, in which, if you stand back from the painting, you see continuous figures, but when you go up close to them you see that they're made by tiny little dots of paint which fuse together in your eyes and in your brain from a distance, but are discreet and individual.

And the observer who observers a pointillist painting is performing an action, is making the phenotype out of that underlying genotype, so to speak, by the intervention of their eyes and their central nervous systems. In the same way, our genotype is converted into a phenotype through the developmental process which is occurring in a particular environment. And every environment is different, and environments are changing all the time.

So there's a very complicated relationship between genotype and phenotype. People who say, "Well, if only I knew all your genes I'd know exactly all about you," are wrong. Indeed, the notion that if I cloned an individual by reproducing that person's genes in another individual, that the cloned individual would be identical with the ones from which the genes came, is wrong.

When I was a child, the most famous people in the world were the Dionne Quintuplets. The Quintuplets were five girls born in rural Quebec, all identical quintuplets. And they were dressed alike and they had their hair done alike and they looked alike, and they were put into a kind of zoo by their parents and by the doctor who delivered them and by the province of Ontario. And everybody looked at them and they were made as alike as they could be so they'd be the wonder of the modern age. They were clones of each other.

But in fact, when they got older, when they left this artificial environment, they became quite different from each other. A couple became nuns, some were married and some not, two died and three are still alive - I think a third one died recently. One was schizophrenic, the others weren't. They were as different from each other as any five girls could be, although they still looked pretty much alike.

And that's the important point: that although a lot of our morphology, a lot of our facial features appear not to be greatly influenced by environmental variation, our personalities clearly are tremendously influenced by it, and our abilities. And the Dionne quintuplets are a wonderful example.

Is it possible that genes could hold the key to social behaviors?

People are always talking about genes for things - the genes for athletic ability, the genes for making money, the genes for intelligence. And you have to be very careful. Even when there are genes that influence those things, to talk about them as genes for that is not so clear. And a friend of mine gave me a wonderful example. He said, "I know where the genes for knitting are." And I said, "How can you know where those genes are; what does that mean?"

And he said, "Oh, the genes for knitting are clearly on the X chromosome, the *** chromosome. Why? Because, after all, all the people I know who knit have two x chromosomes, and everybody I know who has one X chromosome and one Y chromosome doesn't knit, so the gene for knitting has to be on the X chromosome." And he's right, by the way, that that's the standard method used by geneticists: you find some genetic marker and you see that everybody who has that genetic marker has this trait, everybody who has a different genetic marker has another trait, so you've discovered the gene for it.

Now, when I say the gene for knitting, you're going to laugh, you're going to say, "That's silly. There can't be a gene for knitting. I know why people knit." And the reason that we laugh is because we know the whole story about the gene for knitting. We know that the genes on the X and Y chromosome are for plumbing, and X chromosome people have one kind of plumbing and people with a Y chromosome have a different kind of plumbing. Depending on which plumbing you're born with, you're socialized as either a female or a male. And if you're socialized as a female, one of the things you learn to do is to knit, and if you're socialized as a male, you don't learn to knit.

So, of course, people with two X chromosomes knit and people with one X and one Y don't knit. But you wouldn't want to say that the genes for knitting are there. The point is, we understand the complete developmental and social story about why people with two X chromosomes knit and people with one X and one Y chromosome don't knit. And what's nice about that story is it was exactly the opposite in the 18th century. In the 18th century the gene for knitting was on the Y chromosome, because only men did hand-knitting, not women!

And the reason why men gave up hand-knitting and left it their wives to do at home is because someone invented the knitting machine and the men went into the factory and did knitting on knitting machines and left the now economically useless work to their wives at home. So maybe what we should say that we know that the X chromosome has the genes for doing economically useless work, and the Y chromosome for doing economically useful work.

When you put it in those terms, when you really know the complete story, you stop talking about genes for this and genes for that, and you talk about genes having some influence on certain physiological anatomical traits, which are then used as cues by other people.

So, let's talk about race. I know where the genes for being incarcerated are. They're the skin color genes. Now, that doesn't mean that those genes cause you to be incarcerated. What those genes do is to cause you to have a certain skin color, and social relations and social arrangements are such that people who have dark skin color are incarcerated more than people who don't have dark skin color, but the genes don't make you incarcerated. You have to make that distinction very clearly.

What do you think about new trends in genetics research?

The so-called "new genetics", which just puts the action of these biological factors onto a molecular scale, is still as deterministic as ever. People who are doing molecular genetics, who are mapping genes in human beings, are trying to find the genes for schizophrenia, the genes that are responsible for all sorts of diseases.

The editor of Science magazine, the most prestigious general science magazine, once was asked why we should spend a lot of money on the human genome project when we have all those poor people and homeless people out there, and his response was, "The best way to get rid of homelessness is to study people's genes because homelessness is in the genes."

So the genome project and molecular genetics are simply a new manifestation of an old idea - or they're created with that same bias, namely, the reason we're studying all the genes is because genes determine everything. If you didn't think genes determined what was really important in life, then why would you go and spend all this money and time studying the human genome?

Look, people said, when the human genome project was floated, once we know what the human genome is, when we see all the genes, we'll know what it is to be human. A very famous biologist said that. So if you really think you'll learn what it is to be human by studying human genes, that's why you study them. But of course, we won't know what it is to be human by studying the genes. That's the error. But nevertheless, that's what the modern manifestation of biological determinism is.

Let's take the argument [about genes and homelessness] as the editor meant it. What he's saying is, Why are people homeless? Many homeless people are de-institutionalized mentally ill people or people who have been on drugs or things of that kind. Why are they on drugs? Because they have a biological dependency on drugs. Why are they mentally ill? Because they have genes that make them mentally ill. So that was his reasoning.

Homelessness is not, for him, simply the usual manifestation of economic inequality. People who are homeless are homeless because they're in one way or the other sick, and knowing the genes will cure all the diseases. That's his claim. Especially drug dependency, schizophrenia, manic depression, and so forth. They're all due to genes according to that view. Of course, people have been struggling to find the genes for schizophrenia and manic-depressive syndrome for a long time and they haven't found them. Or rather, they keep planning to find them and then six months later they write a paper saying, "Oh, we made a mistake. They're not there."

Is biological determinism another form of racism?

Biological racism is just another manifestation of the belief that everything is in the genes. So of course, if people in Africa are not as well off as people in Europe, it's because they have genes that make them less intelligent and less ambitious, and so on. And the beauty of the race business is that you can identify people by just looking at them. You don't even have to look at their genes because one manifestation of their genes is there - namely skin color or eye shape or hair shape - and then that's the key to everything.

So racism, that kind of biological racism is just part of the general ideology that everything important is in the genes. And of course, if people look different then they must have different genes, and to some extent they do have different genes. And that will explain why slaves were black and masters were white. So racism is part and parcel of that whole thing.

Where do our ideas of biological determinism come from?

Biological determinism, which is a desire to understand social inequality, was really built into most 19th century English literature. ****ens, whose the great mystery novelist of the 19th century - all of his mysteries are about the same thing: How do we explain the character people have? Is it upbringing or is it internal? And he believed it was internal.

Oliver Twist is the most famous example of that. You have to remember Oliver Twist was born in the workhouse, which was the place you had to go to get relief after the New Poor Law of 1834. And his mother was in the workhouse. He was born in the workhouse, he had no education, he was living with all these other kids on gruel, picking oakum, doing all the things that little kids in the workhouse did.

And then when he left the workhouse without any education, without any culture, without anything, we find him on the road to London. And he meets on the road to London the Artful Dodger, a kid somewhat older than he was, a teenager. And the contrast between Oliver and the Artful Dodger which is drawn by ****ens is extraordinary. Because the Artful Dodger doesn't speak good English; he drops all his G's; that's the thing that you would expect a poor kid from the slums of London to do. And here's Oliver; he's described as a delicate child, he uses the subjunctive, his grammar is perfect. Where did he learn all that - in the workhouse, the most degraded institution of 19th century Britain?

Well, that's the mystery. The mystery of Oliver Twist is how do we explain the contrast in character between Oliver Twist on the one hand and the Artful Dodger on the other, both of whom were brought up under essentially the same miserable circumstances.

And at the end of the book you discover that Oliver actually had upper-middle class parents. And even though he never saw them because his mother died in childbirth and he never saw his father, the true nature of that upper-middle class "blood" came out in him, and so he was a child of great moral character. He was honest, he was delicate, he used good English, and so on. And that was a working out of that notion, that what really matters about character is what's inside, not what's outside.

And he's not the only one. There's the wonderful story of George Elliott, Daniel Deronda, one of George Elliott's heroes. We're told right away he's the adopted son of an English baroness, and he has all the behavior of the young lord. We meet him in a fashionable watering place and gambling casino in Germany.

And then mysteriously around the age of 20 or 21, he falls in love with a Jewish woman. Now this is early 19th century Britain. That doesn't happen every day of the week. The baron falls in love with a Jewish woman. He learns the Talmud, he converts, and he becomes a Zionist; he actually is one of the earliest people to want to go to Palestine. What's the secret? How do you understand that strange business?

It turns out - and you only discover this at the end of the book - that his mother is a famous Jewish actress who he finally meets when he's an adult and it all came through, and he became what his genes made him. So ****ens is not the only one. And that's true in French literature, it's true in all literature of the 19th century.

Aren't groups like Icelanders genetically distinct because they've been more isolated?

Iceland has been in the news a lot recently because the Icelandic government has awarded the entire Icelandic genome to a private company to exploit. The claim of this company is that the reason why they want to have the genotypes of all Icelanders is because Icelanders are uniquely homogenous people. And why are they uniquely homogenous? Because, the story is, Iceland was founded in the 9th century by people who came from Norway - a very small number of people who came from Norway, just these immigrants. There was nobody in Iceland when they arrived - that's true - and all Icelanders at the present time are descended from those few immigrants at the very beginning, and therefore Icelanders are all related to each other very closely, and therefore if somehow we could study their genes we could find the genes for disease and other things because everybody's related to everybody, and we could carry out the pedigree.

And so the whole thing is based on the claim that Iceland is extremely homogenous, genetically. Now, that's bolstered by the fact that Icelanders speak a language which elsewhere has been dead for 1500 years; that is to say, they speak a form of Old Norse which is related to Norwegian and Swedish but very different. And also they are claimed all to look alike - they're all sort of reddish-haired or blond and so on - and they're isolated and they all know each other; it's a very small country, only a couple hundred thousand people.

So all of that comes together, this notion that Iceland is a genetic isolate, a few people came there, they've been genetically isolated from everybody ever since, and that's why they speak this crazy language and everything is homogenous.

Now, the trouble is that we know that that's not true, and we know it from a source which is in one sense the source of Icelandic national pride, which is the Icelandic Sagas. The Icelandic Sagas, which were composed or spoken verbally during the Middle Ages by a variety of Icelandic authors and eventually written down, tell us the story of the founding of Iceland, of the wars that the Icelanders, the Vikings, engaged in.

And they give this impression at first that it's a very homogenous society. But when you begin to read the sagas, what you discover is that those early Icelanders, those Vikings, were in fact making a living doing exactly the same thing that the Ancient Greeks were doing: namely, half the time they spent farming, and then half the time they were pirates. They got in their boats, and they went around raping and pillaging and taking slaves and just warring everywhere, and that's what Vikings were. Vikings were pirates. And they didn't try to excuse it; that was the way of life the Sagas described.

And in the process of that piratical existence, they took slaves, they brought people back to Iceland from other countries. There a wonderful place in I think it's Egil's Saga, which is a story of a guy who wants to buy a concubine. So he goes to Russia and he deals with a Russian trader, and the Russian trader asks him a certain price for this concubine. He said he had a dozen of these women in his hut. And the Icelander says, "Wait a minute, I'm not going to pay that. That's much more than the usual price for a woman slave."

So there was a usual price, which meant that Icelanders were doing this all the time. They were getting women and bringing them back. If you look around northern Scotland, you see lots of town names - this "ness" and that "ness" - Loch Ness, Inverness, so on. Ness is an Iceland word; it means cape. Those are all the places the Icelanders landed and took their slaves. One of the sagas is all about the fighting in the Orkney Islands and how the Icelanders landed in the Orkneys and established their position there and so on.

So Iceland, in fact, is a place made up, yes, partly of descendants of those early Viking ancestors who fled from Norway to escape the king, but in large part also from slaves they took, from people they brought from all over, and became part of the Icelandic genetic pool. So Iceland turns out, in fact, when you look at Icelanders, when you look at their proteins, you look at their DNA, they turn out to be not any more genetically homogenous than Swedes, Germans, English, French, all of Northern Europe. They look like a typical Northern European country.

Besides I read an article somewhere that they recently were able to decipher the human genes that are responsible for our race - and imagine that: out of millions and millions of letters in our genes it is ONE SINGLE letter that defines human race!